21216232263251 has 12 divisors (see below), whose sum is σ = 22395061094472. Its totient is φ = 20096523654624.

The previous prime is 21216232263241. The next prime is 21216232263377. The reversal of 21216232263251 is 15236223261212.

It is not a de Polignac number, because 21216232263251 - 2¹⁰ = 21216232262227 is a prime.

It is a super-2 number, since 2×21216232263251² (a number of 27 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21216232263241) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 2108186 + ... + 6846671.

It is an arithmetic number, because the mean of its divisors is an integer number (1866255091206).

Almost surely, 2^{21216232263251} is an apocalyptic number.

21216232263251 is a deficient number, since it is larger than the sum of its proper divisors (1178828831221).

21216232263251 is an equidigital number, since it uses as much as digits as its factorization.

21216232263251 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8961458 (or 8961439 counting only the distinct ones).

The product of its digits is 103680, while the sum is 38.

The spelling of 21216232263251 in words is "twenty-one trillion, two hundred sixteen billion, two hundred thirty-two million, two hundred sixty-three thousand, two hundred fifty-one".